Ministry of Secondary Education Republic of Cameroon Progressive Comprehensive High School Peace – Work – Fatherland & PCHS Mankon – Bamenda School Year 2013/2014 Department of Computer Studies INTRODUCTION TO COMPUTER SOFTWARE Class: Comp. Sc & ICT A/L By: DZEUGANG PLACIDE Computer hardware is only as effective as the instructions we give it, and those instructions are contained in software. Software not only directs the computer to manage its internal resources, but also enables the user to tailor a computer system to provide specific business value. This chapter aims to: - Define software and state the main difference between hardware and software - Distinguish the main differences between application software and system software - Classify the different type of application software by categories with examples in each category Table of Contents I. INTRODUCTION TO SOFTWARE .............................................................................................. 2 I.1 Definition of software .................................................................................................................... 2 I.2 Relation between hardware and software ...................................................................................... 2 I.3 Qualities of a good software .......................................................................................................... 2 I.4 Ways of acquiring computer software ........................................................................................... 3 II. CLASSIFICATION OF SOFTWARE ............................................................................................ 3 II.1 Classification of software based on task ...................................................................................... 3 II.2 Classification of software based on source .................................................................................. 9 II.3 Classification of software based on licence.................................................................................. 9 II.4 Other type of software ................................................................................................................ 11 Visit www.dzplacide.overblog.com for further learning tools for ICT & Comp. Sc Page 1 Topic : Computer Software System Par DZEUGANG PLACIDE I. INTRODUCTION TO SOFTWARE I.1 Definition of software Software, by definition, is the collection of computer programs, procedures and documentation that performs different tasks on a computer system. It actually tells the computer what to do and how to do it. Software may enter the computer through one of following three ways. (i) I may be build into the computer circuit in the form of firmware. (ii) It may be loaded into the computer from a secondary storage device such as CD- ROM or hard disk drives (iii) It is also be typed into the computer with the aid of the keyboard and programming tools I.2 Relation between hardware and software Software refers to the computer programs that are loaded into a computer system, and hardware refers to all the visible devices, which are assembled together to build a computer system. The blending of software and hardware gives life to a computer system. Even though hardware is the physical part of a computer, it is nothing unless it has software to control it. Hardware and software then share a special relationship. If hardware is the 'heart' of a computer system, software is its 'soul'. Both are complimentary to each other. Hardware is of no use without software and software cannot be used without hardware. I.3 Qualities of a good software Some of the most essential attributes of good software include (a) Usability: This is the ease and convenience with which software can be used by human being. This is affected by technologies such as the Human-Computer Interface (b) Efficiency: This is the degree with which software fufills its purposes without waste of resources (c) Portability: It is the ease with which software can be used in other computer systems different from the currents one. (d) Reusability: This is the ease with which software can be reused to design other software. (e) Maintainability: this is the ease with which modifications can be made to satisfy new requirements or to correct deficiencies. Well designed software should be flexible enough to accommodate future changes that will be needed as new requirements come to light. (f) Security: This is the with which software is able to protect its data against unauthorized access and to withstand malicious interference on its operations Visit www.dzplacide.overblog.com for further learning tools for ICT & Comp. Sc Page 2 Topic : Computer Software System Par DZEUGANG PLACIDE (g) Reliability: This is the frequency and extends to which software fails to perform its functions under normal operating circumstances. (h) Understandability: It is the ease with which software can be understood by computer users. (i) Completeness: This is the characteristic whereby, the software possesses all of its parts, each of them being fully developed. (j) Correctness: This is the degree with which software meet its specified requirements. (k) Robustness: This is the degree with which software resist to users manipulations errors (l) ... I.4 Ways of acquiring computer software Software can enter the computer through different channels. Some of the common ways of acquiring computer software include: (i) Buying the computer: when you buy a new computer from the shop, you are usually supplied with some software for free, from the computer manufacturer (ii) Buying the software from a shop: (iii) Downloading the software from a website for free (freeware) or after paying some money to the vendor (iv) Ordering from the vendor either by email, fax or postal letter. Here you also need to pay for the product before it is sent to you. (v) Copying from other people‘s machines: This is what most Cameroonians do and it is what referred to as software piracy. Software piracy is illegal and therefore punishable by law II. CLASSIFICATION OF SOFTWARE Computer software can be organized into categories based on common function, task, or field of use. We can then categorize software in different ways. II.1 Classification of software based on task Based on the kind of task they perform, software can be divided into two major groups: System software and application software. The diagram below gives a simplified hierarchical organization of the main parts of software in a general-purpose computer. At the highest level of this hierarchy lies the application software, whose services are carried out by the underlying system software. The devices of the system software are then executed by the underlying hardware components Computers operate by executing software programs. This involves passing the instructions from the application software, through the system software to the hardware that ultimately Visit www.dzplacide.overblog.com for further learning tools for ICT & Comp. Sc Page 3 Topic : Computer Software System Par DZEUGANG PLACIDE receive the instruction as machine code. Each instruction causes the computer to carry out an operation such as data transmission, data processing, data storage or data control. II.1.1 System software System software is a type of computer software that controls the operation of the computer and provides facilities that extend the general capabilities of the machine. This provides the basic functions for computer usage and helps to run the computer hardware and system. It includes a combination of the following: 1) Operating system An operating system is a group of computer programs that coordinates all the activities among computer hardware devices. This is the most important type of system software in a computer. A user can‘t run an application program on the computer except it is self booting without the Operating System. Operating systems are contained in almost all devices including mobile phones. (to be extended in the next chapter) Functions of an operating system An operating system executes many functions to operate computer system efficiently. Among them, four essential functions are the followings. Resource Management: An operating system manages a collection of computer hardware resources by using a variety of programs. It manages computer system resources, including its CPU, primary memory, virtual memory, secondary storage devices, input/output peripherals, and other devices. For example, most operating systems now are plug and play which means a device such as a printer will automatically be detected and configured without any user intervention. Task Management: The function of the operating system that controls the running of many tasks. It manages one program or many programs within a computer system simultaneously. That is, this function of operating system manages the completion of users' tasks. A task management program in an operating system provides each task and interrupts the CPU operations to manage tasks efficiently. Task management may involve a multitasking capability. File management: This is a function that manages data files. An operating system contains file management programs that provide the ability to create, delete, enter, change, ask, and access of files of data. The operating system keeps track of where files are located on the hard drive through the type of file system. The type two main types of file system most used are File Allocation table (FAT) or New Technology File system (NTFS). User Interface: